Following a brief frame story with a live-action narrator, the main story begins on a dark and stormy night as the wealthy master of the "Gruesome Gables" mansion is reading a book. He informs the audience that, according to the book, he is about to be "bumped off". A duo of threatening messages inform him that he will be killed at midnight. Shortly after his apparent death, a police detective arrives at the mansion to investigate the murder. The victim's servants are acting suspiciously. The mansion is filled with surreal pitfalls, strange characters, and booby traps, with the detective increasingly bewildered. After capturing the masked killer, the detective unmasks him. The killer is not among the suspects which the detective has previously met, he is simply the anonymous host from the frame story.
—Dimos I